Comparison of Efficacy and Safety of Two Dosages Dabigatran versus Warfarin in Patients with Persistent and Long-standing Atrial Fibrillation Undergoing Electrical Cardioversion

Introduction: The most important factor for efficacy and safety for patients with atrial fibrillation (AF) undergoing electrical cardioversion (ECV) is appropriate use of oral anticoagulant (OAC) therapy. Dabigatran is a possible alternative OAC therapy before and after ECV versus therapy with warfarin. Methods: We have analysed the data collected before, during and after ECV in 1046 patients (pts) undergoing ECV. All pts had AF, 885 defined as persistent and 161 defined as long-acting, mean CHA2DS2 VASc score was 3.1 ± 1.8, 735 had one or two ECV in anamnesis. 628 (60%) pts started the use of dabigatran, (405 pts 150 mg twice or 223 pts 110 mg twice) before ECV for at least 21 day, 418 (40%) started warfarin therapy, 21 day start after INR was in range 2.0 - 3.0. Transesophageal echocardiography (TEE) was encouraged before ECV in all groups for pts with CHA2DS2VASc score ≥ 3, markedly left atrial dilatation and AF duration ≥ 6 months. ECG and Echo-kg data were analysed 30 and 90 days after ECV. Results: ECV was successful after first shock in 962 (91.7%) pts, in total successful ECV - in 1029 (98.37%) pts. Left atrial thrombi were detected on TEE before ECV in 7 pts in dabigatran group and 12 pts in warfarin group, so, pts continued OAC therapy for one month, and TEE had been performed again. 3 pts in dabigatran (150 mg twice) group and 2 pts in warfarin group were free of thrombus and have been referred to ECV. Average time for treatment before ECV was significantly lower for dabigatran (25 days) vs warfarin (44 days, p<0.01). Stroke and systemic embolism rates at 90 days were lower in both dabigatran group (0.1%) vs warfarin group (1.4%). There was no difference in analysis of events between TEE and non-TEE pts. Dabigatran pts had significantly lower clinical relevant bleeding rate vs warfarin (D 110 mg 0, D 150 mg 0.47% vs W 2.87%, p<0.04). Conclusions: Dabigatran 150 mg and 110 mg twice is a safe, effective and reasonable alternative to warfarin for patients undergoing ECV despite CHA2DS2VASc risk score and AF duration. The frequencies of stroke and embolic events were lower in dabigatran 150 mg and 110 mg versus warfarin with lower bleeding rates within 30 and 90 days after ECV. Patients undergoing dabigatran therapy have shorter time before procedures and can save time for INR test in normal range.